I keep getting a very sore back of my neck about a day after drinking alcohol, is this normal?

Not really!: Could you be participating in other physical activities when you drink alcohol that perhaps you don't remember the next day? Or could be that you sleep in an unusal position when you drink before bedtime?

Interesting, No: "Is that normal": No. But, what is the mechanism? Not clear. Both sides, back of neck? Any other muscle involvement? If both sides and no other symptoms then maybe stress issues associated with drinking. Do you get migraine or tension headaches? If one side then maybe something to do with how you sleep. If other symptoms then possibilities expand.